Fast faraday cup for measuring the longitudinal distribution of particle charge density in non-relativistic beams

ABSTRACT

A Fast Faraday Cup includes a group of electrodes including a grounded electrode having a through hole and a collector electrode configured with a blind hole that functions a collector hole. The electrodes are configured to allow a beam (e.g., a non-relativistic beam) to fall onto the grounded electrode so that the through hole cuts a beamlet that flies into the collector hole and facilitates measurement of the longitudinal distribution of particle charge density in the beam. The diameters, depths, spacing and alignment of the collector hole and the through hole are controllable to enable the Fast Faraday day cup to operate with a fast response time (e.g., fine time resolution) and capture secondary particles.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a Continuation in Part of U.S. application Ser. No.16/101,982, entitled “FAST FARADAY CUP FOR MEASURING THE LONGITUDINALDISTRIBUTION OF PARTICLE CHARGE DENSITY IN NON-RELATIVISTIC BEAMS,”filed on Aug. 13, 2018. application Ser. No. 16/101,982 is incorporatedherein by reference in its entirety.

STATEMENT OF GOVERNMENT RIGHTS

The invention described in this patent application was made withGovernment support under the Fermi Research Alliance, LLC, ContractNumber DE-AC02-07CH11359 awarded by the U.S. Department of Energy. TheGovernment has certain rights in the invention.

TECHNICAL FIELD

Embodiments are generally related to the field of charged particledetectors. Embodiments also relate to Faraday cups used for measuringcurrent in a beam of charged particles, and more particularly to a FastFaraday Cup (FFC). Embodiments further relate to an FFC that measuresthe longitudinal distribution of particle charge density innon-relativistic beams.

BACKGROUND

Response time of an electronic device is related to its bandwidth in thefrequency domain. The wider the bandwidth, the faster the response time.As such, there is a demand for wide bandwidth devices that provide veryfast response time.

A Faraday cup is a simple detector of charged particle beams. A Faradaycup typically includes an inner cup concentrically located within agrounded outer cup. Faraday cups are known for their large dynamic rangeand ability to function in a wide range of environments, including forexample, varying atmospheric pressures.

Well-designed and shielded Faraday cups have been reported to measurecurrents down to, for example, 10⁻¹⁵ A, corresponding to 10⁴ chargedparticles per second. While electron multipliers are more sensitive,Faraday cup detectors provide quantitative charge measurements with highprecision and stable performance. For instance, electron multipliers aresusceptible to degradation over time due to sputtering of the electronconversion material, and the gain of these detectors can vary dependingon the mass of the impending ions.

Faraday cups can be used to measure current in a beam of chargedparticles. A Faraday cup may include a conducting metallic enclosure orcup that captures a charged particle beam in a vacuum. An electricalconnection between the Faraday cup and a measuring instrument relays thecurrent to the measuring instrument. While Faraday cups are useful, mostalso have limited bandwidth.

Furthermore, in some applications incoming high energy charged particlesmay impinge on a target, causing the sputtering effect. This occurs whenelectrons and atoms associated with the target are ejected out of thetarget. This sputtering effect negatively impacts measurement accuracyand creates a noisy background.

The methods and systems disclosed herein address these limitations byproviding embodiments which have very wide bandwidth and very fastresponse time, as further detailed herein.

BRIEF SUMMARY

The following summary is provided to facilitate an understanding of someof the innovative features unique to the disclosed embodiments and isnot intended to be a full description. A full appreciation of thevarious aspects of the embodiments disclosed herein can be gained bytaking the entire specification, claims, drawings, and abstract as awhole.

It is, therefore, one aspect of the disclosed embodiments to provide foran improved charged particle detector.

It is another aspect of the disclosed embodiments to provide for animproved Fast Faraday Cup that does not require the use of a biasingvoltage and therefore a biasing circuit.

It is a further aspect of the disclosed embodiments to provide for aFast Faraday Cup composed of a plurality of electrodes including atleast a grounded electrode and a collector electrode.

It is a further aspect of the disclosed embodiments to provide for aFast Faraday Cup that measures the longitudinal distribution of particlecharge density in non-relativistic beams.

The aforementioned aspects and other objectives and advantages can nowbe achieved as described herein. A Fast Faraday Cup is disclosed, whichincludes a plurality of electrodes including a grounded electrode havinga through hole and a collector electrode configured with a blind holethat functions as a collector hole. The electrodes are configured toallow a beam (e.g., a non-relativistic beam) to fall onto the groundedelectrode so that the through hole cuts a beamlet that flies into thecollector hole and facilitates measurement of the longitudinaldistribution of particle charge density in the beam. The diameters,depths, spacing and alignment of the collector hole and the through holeare controllable to enable the Fast Faraday day cup to operate with afast response time (e.g., fine time resolution) and capture secondaryparticles.

The grounded electrode includes a hollow portion configured to meetspacing requirements of a coaxial transmission line. In addition, theFast Faraday Cup can be configured with a coaxial cylindrical topologythat includes at least two ports. The coaxial cylindrical topologyincludes the coaxial transmission line with a center conductor and anouter conductor. In addition, the collector electrode comprises at leasta part of the center conductor. The grounded electrode includes a partof the outer conductor. The grounded electrode includes a hollow portionconfigured to meet spacing requirements of the coaxial transmission lineand match to adjoining coaxial transmission lines.

Thus, in an example embodiment, an improved Fast Faraday Cup can beimplemented, which includes two features: (1) at least two electrodesthat include a “grounded electrode” with a small through hole (ID<1 mm)and a “collector electrode” with a small blind hole, to measurenanosecond time structure of bunched ion beam. The diameters, depths,spacing of the two aligned holes are controlled to enable this device tohave fast time response and capture secondary particles that interferethe measurement of the beam; and (2) the two electrodes are customconfigured in a coaxial cylindrical topology so that the device has awide bandwidth of, for example, 20 GHz, 50 Ohm impedance and twoconnection ports. The combination of (1) and (2) above constitutes aFast Faraday Cup capable of resolving details of the longitudinaldistribution of beam at the level of <0.1 nanosecond without using anybiasing circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, in which like reference numerals refer toidentical or functionally-similar elements throughout the separate viewsand which are incorporated in and form a part of the specification,further illustrate the present invention and, together with the detaileddescription of the invention, serve to explain the principles of thepresent invention.

FIG. 1 illustrates a cut-away sectional view of a Fast Faraday Cup(FFC), in accordance with an example embodiment;

FIG. 2 illustrates an image of the FFC shown in FIG. 1 , in accordancewith an example embodiment;

FIG. 3 illustrates a schematic diagram depicting how a beam bunch is cutinto a beamlet by the components of the FFC, in accordance with anexample embodiment;

FIG. 4 illustrates a graph depicting beam measurement results of a FFC,in accordance with an example embodiment;

FIG. 5 illustrates another graph depicting beam measurement results of aFFC, in accordance with another example embodiment;

FIG. 6 illustrates yet another graph depicting beam measurement resultsof a FFC, in accordance with another example embodiment;

FIG. 7 illustrates a graph depicting insertion loss data for a FFC, inaccordance with an example embodiment;

FIG. 8 illustrates another graph depicting insertion loss data for aFFC, in accordance with another example embodiment;

FIG. 9 illustrates a side view of a FFC, in accordance with an exampleembodiment;

FIG. 10 illustrates a perspective view of a FFC, in accordance with anexample embodiment; and

FIG. 11 illustrates a side view of a FFC, in accordance with an exampleembodiment.

DETAILED DESCRIPTION

The particular values and configurations discussed in these non-limitingexamples can be varied and are cited merely to illustrate one or moreembodiments and are not intended to limit the scope thereof.

Subject matter will now be described more fully herein after withreference to the accompanying drawings, which form a part hereof, andwhich show, by way of illustration, specific example embodiments.Subject matter may, however, be embodied in a variety of different formsand, therefore, covered or claimed subject matter is intended to beconstrued as not being limited to any example embodiments set forthherein; example embodiments are provided merely to be illustrative.Likewise, a reasonably broad scope for claimed or covered subject matteris intended. Among other things, for example, subject matter may beembodied as methods, devices, components, or systems/devices.Accordingly, embodiments may, for example, take the form of hardware,software, firmware or any combination thereof (other than software perse). The following detailed description is, therefore, not intended tobe interpreted in a limiting sense.

Throughout the specification and claims, terms may have nuanced meaningssuggested or implied in context beyond an explicitly stated meaning.Likewise, phrases such as “in one embodiment” or “in an exampleembodiment” and variations thereof as utilized herein do not necessarilyrefer to the same embodiment and the phrase “in another embodiment” or“in another example embodiment” and variations thereof as utilizedherein may or may not necessarily refer to a different embodiment. It isintended, for example, that claimed subject matter include combinationsof example embodiments in whole or in part.

In general, terminology may be understood, at least in part, from usagein context. For example, terms, such as “and”, “or”, or “and/or” as usedherein may include a variety of meanings that may depend, at least inpart, upon the context in which such terms are used. Typically, “or” ifused to associate a list, such as A, B, or C, is intended to mean A, B,and C, here used in the inclusive sense, as well as A, B, or C, hereused in the exclusive sense. In addition, the term “one or more” as usedherein, depending at least in part upon context, may be used to describeany feature, structure, or characteristic in a singular sense or may beused to describe combinations of features, structures, orcharacteristics in a plural sense. Similarly, terms such as “a”, “an”,or “the”, again, may be understood to convey a singular usage or toconvey a plural usage, depending at least in part upon context. Inaddition, the term “based on” may be understood as not necessarilyintended to convey an exclusive set of factors and may, instead, allowfor existence of additional factors not necessarily expressly described,again, depending at least in part on context. Additionally, the term“step” can be utilized interchangeably with “instruction” or“operation”.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art. As used in this document, the term “comprising” means“including, but not limited to.” The term “at least one” conveys “one ormore”. The term “at least two” conveys “two or more”.

Note that as utilized herein, the term “Faraday cup” generally refers toa metal (conductive) cup configured to catch charged particles. Theresulting current can be measured and used to determine the number ofions or electrons hitting the Faraday Cup. The Faraday cup is namedafter Michael Faraday who first theorized ions around 1830.

The disclosed embodiments are directed to a Fast Faraday cup usingcoaxial cylindrical topology for measuring the longitudinal chargedensity of a charged particle beam. The system can generally comprise agrounded hollow metal body, a center metal rod inside the groundedhollow metal body, and two hollow dielectric cylinders filling twoseparate portions of the grounded hollow metal body. The grounded hollowmetal body can include a small aperture through which charged particlescan pass and impinge a very small portion of the center metal rod. Thecenter metal rod collects the impinging charged particles and transmitsthe electrical signals generated by the impinging charged particlesthrough the adjacent portions of the system to end ports that can beconnected to measuring device(s) such as a wide bandwidth fastoscilloscope via coaxial transmission lines.

The hollow volume inside the metal body can be cylindrical in shape. Forthe purpose of transmitting the signals to the two end ports, the centermetal rod and the grounded hollow metal body together constitute aspecial coaxial transmission line. The metal rod is the inner conductor,and the hollow metal body is the outer conductor. This special coaxialtransmission line can have three different portions: a center portionfor receiving the charged particle, and two dielectric material filledportions. The diameter of the center metal rod and the inner diametersof the hollow metal body are controlled to make all three portions havesame characteristic impedance which allows the system to provide a verywide bandwidth (for example, up to 20 GHz), and gives system a very fastresponse time (for example, up to <0.1 nanoseconds). The small apertureof the hollow metal body also allows the air inside the hollow volume ofthe metal body to be pumped out so that the system can be used in anultra-high vacuum environment.

In certain embodiments, the center metal rod has a receiving hole (alsoreferred to as a capturing hole or dead end hole). The ratio of thediameter to the depth of this hole is controlled, or the hole can beconfigured to be controllable, so that it not only receives all theincoming charged particles but also captures secondary electrons andparticles generated by the impingement of the incoming particles, andprevents them from escaping the metal rod. This capturing functioneliminates the need for extra biasing parts and circuits, used by mostpresent Faraday cups, to generate extra electric field to push thesecondary particles back to the beam target.

It should be noted that the Fast Faraday Cup is capable of measuring thecharge distribution of the charged beam not only in longitudinaldirection (beam trajectory direction), but also in transverse(horizontal or vertical) directions.

FIG. 1 illustrates a cut-away sectional view of a Fast Faraday Cup (FFC)10, in accordance with an example embodiment. The FFC 10 generallyincludes a body 18 that surrounds a collector electrode 14, which inturn is located centrally within a coaxial transmission line 12. Thebody 18 is further configured with a plurality of holes such as holes 5and 7 that extend through the body 18. Because FIG. 1 only illustrateshalf of a FFC 10, it should be appreciated that additional holes arealso provided such as the holes 1 and 3 shown in FIG. 10 . Holes 1, 3and 5, 7 are configured to receive and maintain respective pins orscrews.

The collector electrode 14 (i.e., the “collector”) is configured with asmall blind hole that functions as a receiving hole 4. Note that thereceiving hole 4 functions as a collector hole; thus, the terms“receiving hole” and “collector hole” can be used interchangeably hereinto refer to the same feature. The FFC 10 is further configured with agrounded electrode 16 (also referred to as “ground electrode”)configured with a small through hole or aperture 6 (e.g., ID<1 mm). Thegrounded electrode 16 is generally formed from body 18. The FFC 10 isfurther configured with a generally circular or cylindrical recess 17.The recess 17 hosts a Molybdenum alloy TZM disk 99.

The through hole or aperture 6 of the ground electrode 16 extends from areceiving hole 4 configured in the collector electrode 14 to acollimating hole 19 in the TZM disk 99 located in the recess 17. The TZMdisk 99 (which functions as a shielder) is configured with thecollimating hole 19, which engages with, or forms a part of, the throughhole 6 of the ground electrode 16. In general, a beam 8 falls onto theground electrode 16 and the through hole 6 cuts a small beamlet thatflies into the collector hole 4 (i.e., the receiving hole configuredfrom the collector electrode 14). The diameters, depths, spacing andalignment of the collector hole 4 and the through hole 6 associated withthe grounded electrode 16 are controllable to enable the FFC 10 to havea fast response time (e.g., a fine time resolution) and capturesecondary particles as well.

The collector electrode 14 forms a part of the center conductor of thecoaxial transmission line 12 (e.g., a 50 Ohm coaxial transmission line),which can be configured from a material such as, for example, Teflon.Note that if the collector electrode 14 is an added part, the bandwidthmay be reduced. The geometry of the hollow part within the “groundelectrode” 16 can be configured to meet the spacing requirements of, forexample, the aforementioned coaxial transmission line. The true“grounded electrode” part is actually the center portion of the body 18.The FFC or the body 18 can be divided into three portions, which areshown in more detail in FIG. 9 . These portions are the Teflon filledportion (left and right) which can either comprise, or otherwiseinterface with, the adjoining coaxial transmission lines, and the centerportion which is the grounded electrode depicted in FIG. 9 . One of theadvantages of the disclosed FFC device is that these three parts can beconfigured from one part (i.e., “body”) so that extra soldering andconnecting are not necessary, which is important for very widebandwidth.

FIG. 2 illustrates an image 20 of the FFC 10 shown in FIG. 1 , inaccordance with an example embodiment. Note that in FIGS. 1-2 ,identical or similar parts or elements are generally indicated byidentical reference numerals. The FFC 10 is configured with a coaxialcylindrical topology having two ports 24 and 26, and can support a verywide bandwidth. Although the two ports 24 and 26 are shown in FIG. 2 ,it can be appreciated that additional ports may be implemented in thecontext of other embodiments.

The collector electrode 14 (not shown in FIG. 2 , but depicted in FIG. 1) is located within the body 18 of the FFC 10. Note that the alignmentof the grounded electrode 16 and the TZM disk 99 along with the variousholes such as holes 4 and 19 can be verified through the use of a thinpin 22. That is, the pin 22 can be used as a part of a special machiningand assembling procedure to ensure that the three small holes 4, 6 and19 are precisely aligned and oriented to each other. Note that the TZMdisk 99 (e.g., which has a high melting temperature) is configured as anattached part to protect the entrance area to the grounded electrode 16.Because the TZM disk 99 is attached to the grounded electrode 16, it canbe considered a part of the grounded electrode 16. However, it should beappreciated that the TZM disk 99 and the grounded electrode 16 can alsobe configured as separate components.

The aforementioned TZM disk 99 can be further configured with twocomponents 28 and 30 that may extend into respective holes 41 and 43(i.e., shown in FIG. 10 but not in FIG. 2 ) configured in the body 18.Note that additional components 32, 34, and 36 are shown in FIG. 2 ,which respectively extend through holes 5, 3 and 1. Although not shownin FIG. 2 , an additional component may extend through the hole 7.

FIG. 3 illustrates a schematic diagram depicting how a beam bunch is cutinto a beamlet by the components of a FFC, in accordance with an exampleembodiment. The schematic diagram shown in FIG. 3 generally correspondsto a FFC such as the FFC 10 shown in FIGS. 1-2 . Thus, the collector 14is shown with respect to the grounded electrode 16. A beamlet is alsoshown. An area constituting an orifice is depicted in the center of thegrounded electrode 16. An incoming beam bunch is shown hitting theaforementioned orifice. The aforementioned orifice generally correspondsto the holes 19 and 6 shown in FIGS. 1-2 .

FIG. 4 illustrates a graph 50 depicting beam measurement results of aFFC, in accordance with an example embodiment. FIG. 5 illustratesanother graph 60 depicting beam measurement results of a FFC, inaccordance with another example embodiment.

FIG. 6 illustrates yet another graph 70 depicting beam measurementresults of a FFC, in accordance with another example embodiment. Thebeam test results shown in graph 70 are indicated by two lines 72 and 74and correspond to the information contained in the legend 76. Line 72represents data indicative of Gaussian fit. Line 74 is representative ofFFC (Fast Faraday Cup) data wherein σ_(z)=363.8 ps. The graph or plot 70shown in FIG. 7 generally plots FCC signal [V] data versus Time (psec).

FIG. 7 illustrates a graph 80 depicting insertion loss data for a FFC,in accordance with an example embodiment, at a bandwidth of 20 GHz. Notethat the notch at 1.972 GHz in graph 80 is not related to the testedFFC.

FIG. 8 illustrates another graph 90 depicting insertion loss data for aFFC, in accordance with yet another example embodiment. Graph 90 plotsdata indicative of the insertion loss of a tested FFC plus two 0.141″semi-rigid coaxial cables (e.g., ˜21″ of the total length) and twovacuum feedthroughs. It should be appreciated that the data contained inthe various graphs 50, 60, 70, 80, and 90 are presented for generalillustrative and exemplary purposes only and should not be consideredlimiting features of the disclosed embodiments.

FIG. 9 illustrates a side view of the FFC 10, in accordance with anexample embodiment. FIG. 9 presents another view of the FFC 10 shown,for example, in FIGS. 1-2 . As discussed previously, the true “groundedelectrode” part can comprise the center portion of the body 18. The FFCor the body 18 can be divided into three portions, which are shown inmore detail in FIG. 9 . These portions are the Teflon filled portion(left and right) comprising “adjoining coaxial transmission lines,” andthe center portion comprising the “grounded electrode”. An advantage ofthe disclosed FFC 10 is that these three parts can be configured fromone part (i.e., the “body”) so that extra soldering and connecting arenot necessary, which is important to achieve a very wide bandwidth.

FIG. 10 illustrates a perspective view of the FFC 10, in accordance withanother example embodiment. FIG. 11 illustrates a side view of the FFC10, in accordance with another embodiment. The FFC 10 includes body 18which surrounds the collector electrode 14 located centrally within thecoaxial transmission line 12. The body 18 is configured with a pluralityof holes 1, 3 and 5, 7 that extend through the body 18. The screws 28and 30 are also shown in FIG. 10 and are located above holes 41 and 43.The screws 28 and 30 are located on the grounded electrode 16 asdiscussed previously.

It should be appreciated that the configuration depicted in FIGS. 10-11is that of an alternative embodiment, and that other designs andembodiments can be implemented which vary from the embodiments shown inFIGS. 10-11 and elsewhere herein.

Thus, as described herein a FFC can comprise a coaxial cylindricaltopology for measuring the longitudinal charge density of a chargedparticle beam. The system can include a grounded hollow metal body, acenter metal rod inside the grounded hollow metal body, and two hollowdielectric cylinders filling two separate portions of the groundedhollow metal body. The grounded hollow metal body can have a smallaperture to allow charged particles to pass through and impinge a verysmall portion of the center metal rod. The center metal rod isconfigured to collect the charged particles and transmits the electricalsignals generated by the charged particles through the adjacent portionsof the system to end ports that are connected to measuring device(s)such as a high bandwidth fast oscilloscope.

Note the hollow volume inside the metal body can have a cylindricalshape. Therefor for the purpose of transmitting the signals to the twoend ports, the center metal rod and the grounded hollow metal bodytogether constitute a special coaxial transmission line. The metal rodis the center conductor, and the hollow metal body is the outerconductor. This special coaxial transmission line has three portions: acenter portion for receiving said charged particle, a first portionfilled with dielectric material, and a third portion filled withdielectric material. The diameter of the center metal rod and the innerdiameters of the hollow metal body at the three portions are controlledto make all three portions have the same characteristic impedance, whichenables said system to have a wide bandwidth of up to approximately 20GHz, and enables said system to have fast response time.

It should be noted that the center metal rod has a receiving hole (i.e.,a “capturing hole” or a “dead end hole”). The ratio of the diameter tothe depth of this hole is controlled so that it not only receives theincoming charged particles but also captures secondary electrons orparticles generated by the impinging of the incoming particles, andprevents them from escaping the metal rod. This capturing functioneliminates the need for extra biasing parts and circuits used by most ofpresent Faraday cups to push the secondary particles back to the beamtarget. The small aperture in the hollow metal body also allows the airinside the hollow volume to be pumped out so that the system can be usedin ultra-high vacuum environment.

In certain embodiments, a special manufacturing and assembling methodenables the capturing hole on the center metal rod and the aperture ofthe metal body to be made together (not separately) using electricaldischarge machining after the metal rod and body are assembled. Thisprocess ensures the capturing hole in the metal rod and the aperture ofmetal body are aligned to extremely high accuracy (less than 0.001″ ofmisalignment). This alignment accuracy minimizes the occurrence ofincoming particles falling on the outside of the capturing hole.

Based on the foregoing, it can be appreciated that a number of exampleembodiments are disclosed herein. For example, in one embodiment, a FFCcan be configured, which includes a plurality of electrodes including aground electrode having a through hole and a collector electrodeconfigured with a blind hole comprising a collector hole, wherein theplurality of electrodes are configured to allow a beam to fall onto theground electrode so that the through hole cuts a beamlet that flies intothe collector hole and facilitate a measurement of a longitudinaldistribution of particle charge density in the beam.

In some example embodiments, the aforementioned collector hole andthrough hole can include parameters that are controllable to enable theFFC to perform the measurement with a fast response time of less than0.1 nanosecond and capture secondary particles without requiring a useof a biasing voltage and therefore a biasing circuit. Such controllableparameters can include, for example, the diameter, the depth, thespacing and/or the alignment of the collector hole and the through hole.

In addition, the fast response time can comprise a fine time resolution.In some example embodiments, the ground electrode can be configured witha hollow portion configured to meet the spacing requirements of acoaxial transmission line. In still other example embodiments, the FFCcan be configured with a coaxial cylindrical topology that includes twoor more ports and the aforementioned coaxial transmission line. In stillother example embodiments, the coaxial cylindrical topology can includea coaxial transmission line having a center conductor, wherein thecollector electrode comprises at least a part of the center conductor.

In yet another example embodiment, the aforementioned coaxialcylindrical topology can be configured with a coaxial transmission linehaving a center conductor, such that the collector electrode includes atleast a part of the center conductor. The ground electrode can include ahollow portion configured to meet the spacing requirements of thecoaxial transmission line and match to adjoining coaxial transmissionlines, thereby forming a device having, for example, a wide bandwidth ofapproximately 20 GHz and a fast response time. Note that theaforementioned 20 GHz bandwidth is not a limiting feature of thedisclosed embodiments, but is one possible bandwidth size that can befacilitated by the disclosed device.

Additionally, note that because one transmission line has two ends, bothends can be “matched” in order to achieve excellent performance. Hence,in some example embodiments, the FFC disclosed herein can be configuredwith a coaxial cylindrical topology that includes a coaxial transmissionline, which matches to at least two (i.e., two or more) adjoiningcoaxial transmission lines.

In certain embodiments, A Fast Faraday Cup, can comprise a groundedhollow conducting body, a conducting rod configured inside the groundedhollow conducting body, at least two hollow dielectric cylinders withinthe grounded hollow conducting body, an aperture in the grounded hollowconducting body configured to allow charged particles to reach theconducting rod, and at least two ports operably connected to theconducting rod. The grounded hollow conducting body can further comprisea metal grounded hollow conducting body. The conducting rod can furthercomprise a metal non-grounded hollow conducting cylinder. The hollowportion in the hollow conducting body can be cylindrical. The at leasttwo hollow dielectric cylinders within the grounded hollow conductingbody can comprise two hollow dielectric cylinders within the groundedhollow conducting body. The diameter of the conducting rod and an innerdiameter of the grounded hollow conducting body can be selected to havea substantially matching characteristic impedance. The Fast Faraday Cupcan have a bandwidth of up to 20 GHz. The Fast Faraday Cup can have aresponse time of less than 0.1 nanoseconds. The aperture in the groundedhollow conducting body can be configured to allow a vacuum to be drawnin a hollow volume of the Fast Faraday Cup. The Fast Faraday Cup canfurther comprise a receiving hole in the conducting rod. The ratio of adiameter of the receiving hole to a depth of the receiving hole isselected so that the receiving hole captures incoming charged particlesand secondary particles. The receiving hole is configured to prevent theincoming charged particles and the secondary particles from escaping theconducting rod. A recess can be formed in the grounded hollow conductingbody. A TZM disk can be configured in the recess formed in the groundedhollow conducting body.

In another embodiment a Fast Faraday Cup, comprises a coaxialtransmission line further comprising: a grounded hollow conducting body,a conducting rod configured inside the grounded hollow conducting body,and at least two hollow dielectric cylinders within the grounded hollowconducting body; and an aperture in the grounded hollow conducting bodyconfigured to allow charged particles to reach the conducting rod. Thecoaxial transmission line further comprises three portions comprising acenter portion for receiving charged particles, a first portion filledwith dielectric material, and a second portion filled with dielectricmaterial. The diameter of the conducting rod and an inner diameter ofthe grounded hollow conducting body at the three portions can becontrolled such that the three portions have the same characteristicimpedance.

In another embodiment a method of configuring a Fast Faraday Cupcomprises providing a coaxial transmission line further comprising agrounded hollow conducting body, a conducting rod configured inside thegrounded hollow conducting body, at least two hollow dielectriccylinders within the grounded hollow conducting body, and a through holeand a collector hole, configuring said coaxial transmission line toallow a beam to fall onto said grounded hollow conduct body so that thethrough hole cuts a beamlet that flies into the collector hole andfacilitate a measurement of a distribution of particle charge density inthe beam. The method further comprises controlling a diameter, a depth,a spacing and/or an alignment of the collector hole and the through holeto enable the Fast Faraday Cup to perform the measurement with a fastresponse time of less than 0.1 nanosecond and capture secondaryparticles without requiring a use of a biasing voltage. The methodfurther comprises configuring the coaxial transmission line to match atleast two different adjoining coaxial transmission lines.

It will be appreciated that variations of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. It will alsobe appreciated that various presently unforeseen or unanticipatedalternatives, modifications, variations or improvements therein may besubsequently made by those skilled in the art which are also intended tobe encompassed by the following claims.

What is claimed is:
 1. A Fast Faraday Cup, comprising: a cylindricaltransmission line comprising: a grounded hollow conducting body; aconducting rod configured inside the grounded hollow conducting body;and at least two hollow dielectric cylinders within the grounded hollowconducting body; an aperture serving as a receiving hole in the groundedhollow conducting body configured to allow charged particles to reachthe conducting rod; and at least two ports operably connected to theconducting rod.
 2. The Fast Faraday Cup of claim 1 wherein the groundedhollow conducting body further comprises: a metal grounded hollowconducting body.
 3. The Fast Faraday Cup of claim 1 wherein theconducting rod further comprises: a metal non-grounded hollow conductingcylinder.
 4. The Fast Faraday Cup of claim 1 wherein the hollow portionin a hollow conducting body is cylindrical.
 5. The Fast Faraday Cup ofclaim 1 wherein the at least two hollow dielectric cylinders within thegrounded hollow conducting body comprise two hollow dielectric cylinderswithin the grounded hollow conducting body.
 6. The Fast Faraday Cup ofclaim 1 wherein a diameter of the conducting rod and an inner diameterof the grounded hollow conducting body are selected to have asubstantially matching characteristic impedance.
 7. The Fast Faraday Cupof claim 1 wherein the Fast Faraday Cup has a wide bandwidth of up to 20GHz.
 8. The Fast Faraday Cup of claim 1 wherein the Fast Faraday Cup hasa response time of less than 0.1 nanoseconds.
 9. The Fast Faraday Cup ofclaim 1 wherein the aperture in the grounded hollow conducting body isconfigured to allow a vacuum to be drawn in a hollow volume of the FastFaraday Cup.
 10. The Fast Faraday Cup of claim 1 further comprising: areceiving hole in the conducting rod.
 11. The Fast Faraday Cup of claim10 wherein a ratio of a diameter of the receiving hole to a depth of thereceiving hole is selected so that the receiving hole captures incomingcharged particles and secondary particles.
 12. The Fast Faraday Cup ofclaim 10 wherein the receiving hole is configured to prevent theincoming charged particles and secondary particles from escaping theconducting rod.
 13. The Fast Faraday Cup of claim 1 further comprising:a recess formed in the grounded hollow conducting body, with a aMolybdenum alloy TZM disk therein.
 14. The Fast Faraday Cup of claim 13further comprising: a TZM disk configured in the recess formed in thegrounded hollow conducting body.
 15. A Fast Faraday Cup, comprising: acoaxial transmission line further comprising: a grounded hollowconducting body; a conducting rod configured inside the grounded hollowconducting body; and at least two hollow dielectric cylinders within thegrounded hollow conducting body; and an aperture in the grounded hollowconducting body configured to allow charged particles to reach theconducting rod.
 16. The Fast Faraday Cup of claim 15 wherein the coaxialtransmission line further comprises three portions comprising: a centerportion for receiving charged particles; a first portion filled withdielectric material; and a second portion filled with dielectricmaterial.
 17. The Fast Faraday Cup of claim 16 wherein a diameter of theconducting rod and an inner diameter of the grounded hollow conductingbody at the three portions are controlled such that the three portionshave a same characteristic impedance.
 18. A method of configuring a FastFaraday Cup, said method comprising: providing a coaxial transmissionline further comprising a grounded hollow conducting body, a conductingrod configured inside the grounded hollow conducting body, at least twohollow dielectric cylinders within the grounded hollow conducting body,and a through hole and a collector hole; configuring said coaxialtransmission line to allow a beam to fall onto said grounded hollowconducting body so that the through hole cuts a beamlet that flies intothe collector hole and facilitate a measurement of a distribution ofparticle charge density in the beam.
 19. The method of claim 18 furthercomprising controlling a diameter, a depth, a spacing and/or analignment of the collector hole and the through hole to enable the FastFaraday Cup to perform the measurement with a fast response time of lessthan 0.1 nanosecond and capture secondary particles without requiring ause of a biasing voltage.
 20. The method of claim 18 further comprising:configuring the coaxial transmission line to match at least twodifferent adjoining coaxial transmission lines.